The present invention generally relates to an electronic component having lead terminals led out from respective opposite sides thereof, and a method of manufacturing such an electronic component.
Conventionally, with respect to the electronic components having lead terminals of the type referred to above, there has been known an arrangement as shown in FIG. 1 in which lead terminals 4, each having a circular cross section and formed with a flat portion 4a at one end, are soldered at said flat portions 4a, onto electrodes 2 and 3 respectively formed on opposite end faces of a chip type electronic component element 1, such as a multilayer chip type capacitor or the like, with said electronic component element 1 being covered by a coating layer or resin (not particularly shown). Each of said lead terminals 4 is formed with an annular protrusion 4b for positioning when the electronic component is actually mounted onto a printed circuit board (not shown).
For the manufacture of the electronic component with the lead terminals as described above, a wire of copper or the like having a circular cross section and wound on a reel (not shown) is first led out from the reel and cut into a length approximately two times that of the lead terminal 4, and the piece of wire thus cut off, and curved in an arcuate form due to winding on the reel, is stretched into a straight line.
Thereafter, as shown in FIG. 2(A), the cut wire 4' is bent into a U-shape, and at its bent portion 5, is inserted into one slit 7 of slits 7 and 7' formed in a holder tape 6 made of cardboard, resinous film or the like so as to extend from the front face of the holder tape 6 toward the rear face thereof, and further, led into the other slit 7' so as to be directed from the rear face of said tape 6 onto the front face thereof, with the wire 4' thus being held by the holding tape 6.
Subsequently, the opposite end portions of the wire 4' are processed to form the flat portions 4a and 4a and annular protrusions 4b and 4b, and then, the electronic component element 1 is inserted between the flat portions 4a and 4a as indicated by an arrow A0 in FIG. 2(B) to hold said element 1 therebetween. In the above state, the flat portions 4a and 4a are soldered onto the electrodes 2 and 3 formed at the opposite ends of the electronic component element 1, and then, after or before coating the electronic component element 1 by an external resin layer (not particularly shown), the wire 4' is cut to form the two lead terminals 4 and 4 at a position close to the bent portion 5 as shown by a chain line L0 in FIG. 2(C). Thus, the electronic component having the lead terminals as shown in FIG. 1 may be obtained.
In the electronic component which employs the wire having the circular cross section for the lead terminals as described above, each of the lead terminals 4 and 4 has a possibility to be bent in any direction due to the circular cross section thereof, and therefore, there has been the problem that the lead terminals 4 and 4 are subjected to bending or deformation during manufacture of the electronic component, thus making it impossible to stably hold the electronic component element 1 inserted between the flat portions 4a and 4a of the lead terminals 4 and 4, and consequently, to perfectly solder said flat portions 4a and 4a to the electrodes 2 and 3. Another disadvantage inherent in the manufacture of the conventional electronic component having the lead terminals of the above described type is that there are involved many processings for the wire such as stretching the cut off wire, which was curved in the arcuate shape, into a straight line, and formation of the flat portions 4a and 4a and the annular protrusions 4b and 4b for positioning on the wire, etc.